Magnetron for a microwave oven having a pair of choke coils wound around a core in the same directions

Abstract

A magnetron for a microwave includes a pair of choke coils wound around only one core in same direction thereby forming a unique type choke coil. Ends of the unique type choke coil are connected among a lead-through capacitor, a center lead and a peripheral lead respectively so that the filter circuit includes jointly the unique choke coil. As a result, the magnetron can eliminate radio frequency noise, reduce the heating caused from a power supply, and reduce the volume of the filter box.

What is claimed is: 
     
       1. A magnetron for a microwave oven, comprising, a core;   a pair of choke coils wound around said core, both choke coils are wound in the same direction as a noise flowing direction of radio frequency noise generated from an operating space through a filament to a pair of input terminals for making a pair of output terminals disposed at one end portion thereof and said pair of input terminals disposed at another end portion thereof so that input currents to said pair of input terminals are inverse to each other in their flowing direction at a position where they pass through the core and noises are the same in their flowing direction; and   a filter circuit constituted by connecting said input terminals of said choke coils to a lead-through capacitor and by connecting said output terminals of said choke coils to a center lead and a peripheral lead, respectively.   
     
     
       2. The magnetron according to claim 1, wherein said choke coils are wound in the same direction together so as the magnetic inductive coefficients thereof to be counterbalanced one another so that the input and output terminals are respectively located at the same side.